Method for accessing the left atrial appendage with a balloon-tipped transseptal sheath

ABSTRACT

A method for accessing the left atrial appendage with a balloon-tipped transseptal sheath is disclosed. A transseptal sheath is delivered to the left atrium through the intraatrial septum from the right atrium. The balloon tip may be inflated to prevent the transseptal sheath from falling proximally into the right atrium. The inflated balloon tip permits safe probing and exploration of the left atrial appendage and facilitates safe maintenance of the position of the transseptal sheath within the left atrial appendage while delivering an implantable device to the left atrial appendage.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/607,769, filed Dec. 1, 2006, which claims the benefit of U.S.Provisional Application No. 60/741,113, filed Dec. 1, 2005, the entiretyof which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention relate to delivery and retrieval ofimplantable devices, for example, to and from a left atrial appendage.

2. Description of the Related Art

Methods of percutaneously deploying left atrial appendage implants tothe left atrial appendage of the heart are known to those of skill inthe art. For example, one such method includes percutaneously deliveringa non-steerable transseptal sheath to the right atrium of the heart,crossing the intraatrial Septum (IAS) with the transseptal sheath and adilator, and after advancing the transseptal sheath through the IAS,withdrawing the dilator. When using such method it is often desired toadvance the tip of the transseptal sheath as deep as possible into theleft atrial appendage to assure that access to the left atrium ismaintained.

However, to locate the left atrial appendage and direct the transseptalsheath thereto, these known methods typically use addition equipment anddevices, such as: a J tip guidewire of varying stiffness, a pigtailcatheter, and a transition catheter.

Once the transseptal sheath has been advanced to the left atrialappendage, its morphology is assessed by injecting contrast and viewingunder fluoroscopy. When the proper positioning has been confirmed, theadditional equipment described above is then typically withdrawn fromthe vasculature. During equipment withdrawal the operator takes greatcare to assure that the transseptal sheath is not inadvertently movedand that access to the left atrium is maintained.

The implantable device is then typically deployed. If device recapture,retrieval and/or replacement is indicated, the transseptal sheath'sposition is maintained in the left atrium, the additional equipment anddevices described above are re-deployed, and access to the left atrialappendage is re-established, as described above. When the implant issuccessfully deployed, final contrast injections are performed throughsheath to assess implant condition. The transseptal sheath is thenwithdrawn.

When devices are advanced or withdrawn through the transseptal sheathforces are applied to the sheath wall. Such forces can cause the distalend of the transseptal sheath to become dislodged, moved or misalignedfrom its desired location. It would therefore be advantageous to be ableto access the left atrial appendage and maintain access thereto withoutusing additional equipment and devices.

SUMMARY OF THE INVENTION

In one embodiment, a method of delivering an implantable device to theleft atrial appendage is provided. The method may comprise delivering asheath to the left atrial appendage, inflating a distal end of thesheath within the left atrial appendage to anchor the distal end totissue within the left atrial appendage, and delivering the implantabledevice through the sheath to the left atrial appendage.

In another embodiment, a method of delivering a device to an openingwithin a patient is provided. The method may comprise delivering asheath to the opening, anchoring a distal end of the sheath to tissueadjacent the opening, and delivering a device through the sheath to theopening.

In another embodiment, a method of delivering an implantable device tothe left atrial appendage is provided. The method may comprisedelivering a sheath to the right atrium; advancing the sheath throughthe septum to the left atrium; inflating a distal end of the sheath,thereby providing the sheath with an atraumatic tip; positioning thedistal end of the sheath adjacent the left atrial appendage; anddelivering the implantable device through the sheath to the left atrialappendage.

All of these embodiments are intended to be within the scope of thepresent invention herein disclosed. These and other embodiments of thepresent invention will become readily apparent to those skilled in theart from the following detailed description of the preferred embodimentshaving reference to the attached figures, the invention not beinglimited to any particular preferred embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a patient's heart with a transseptalsheath deployed through the septum.

FIG. 2 is a schematic view of a deployment system delivering an implantto the left atrial appendage.

FIG. 3 is a perspective view of a steerable transseptal sheath with aballoon tip.

FIG. 4 is an enlarged schematic view of the distal end of the steerabletransseptal sheath of FIG. 3.

FIG. 5 is a partial cross sectional view of the balloon tip of FIG. 3 ina deflated state.

FIG. 6 is a partial cross sectional view of the balloon tip of FIG. 5 inan inflated state.

FIG. 7 is a schematic view of an implant deployment system.

FIG. 8 is a schematic cross-sectional view of a portion of the heart,showing a transseptal sheath of one embodiment of the present inventionwithin the right atrium.

FIG. 9 is a cross-sectional view as in FIG. 8, with the guidewirepositioned in the superior vena cava.

FIG. 10 is a cross-sectional view as in FIG. 8, with the transseptalsheath positioned against the wall of the superior vena cava.

FIG. 11 is a cross-sectional view as in FIG. 8, with the transseptalsheath positioned against the fossa ovalis.

FIG. 12 is a cross-sectional view as in FIG. 8, showing tissuedistention or “tenting” as the needle punctures the fossa ovalis.

FIG. 13 is a cross-sectional view as in FIG. 12, showing tissuedistention as the dilator is advanced through the fossa ovalis.

FIG. 14 is a cross-sectional view as in FIG. 13, illustrating thetransseptal sheath, which has been advanced over the dilator and throughthe septum.

FIG. 15 is a cross-sectional view as in FIG. 14, with the dilatorremoved, leaving the transseptal sheath in place across the fossaovalis.

FIG. 16 is a cross-sectional view as in FIG. 15, with the transseptalsheath in place across the fossa ovalis and the balloon tip inflated.

FIG. 17 is a schematic cross-sectional view of a left atrial appendage,showing a transseptal sheath with an inflated balloon tip within theleft atrium near the left atrial appendage.

FIG. 18 is a cross-sectional view as in FIG. 17, with the transseptalsheath positioned centrally within the left atrial appendage.

FIG. 19 is a cross-sectional view as in FIG. 17, with the transseptalsheath positioned deeply within the left atrial appendage.

FIG. 20 is a cross-sectional view as in FIG. 19, with an implantpositioned within the transseptal sheath near the distal end.

FIG. 21 is a cross-sectional view as in FIG. 20, with the implantpositioned within the left atrial appendage, the balloon tip deflated,and the transseptal sheath retracted proximally.

FIG. 22 is a cross-sectional view as in FIG. 21, with the implantexpanded within the left atrial appendage.

FIG. 23 is a cross-sectional view as in FIG. 22, with the balloon tipinflated.

FIG. 24 is schematic cross-sectional view of a left atrial appendage,showing a transseptal sheath with a deflated balloon tip within the leftatrial appendage.

FIG. 25 is a cross-sectional view as in FIG. 24, with the balloon tipinflated to anchor the transseptal sheath within the left atrialappendage.

FIG. 26A is a cross-sectional view as in FIG. 25, with an implantpositioned within the transseptal sheath near the distal end.

FIG. 26B is a cross-sectional view as in FIG. 25, with an implantpartially protruding from the distal end of the transseptal sheath.

FIG. 27 is a cross-sectional view as in FIG. 25, with a balloon tipdeflated.

FIG. 28A is a cross-sectional view as in FIG. 25, with an implantpartially protruding from the distal end of the transseptal sheath.

FIG. 28B is a cross-sectional view as in FIG. 25, with the implantpositioned within the left atrial appendage and the transseptal sheathretracted proximally.

FIG. 29 is a cross-sectional view as in FIG. 25, with the implantexpanded within the left atrial appendage.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS

Embodiments of the present invention provide and maintain safe and easyaccess to the left atrial appendage (“LAA”) of the heart for rapid andaccurate deployment of an implantable device. Similar referencesnumerals will be used to designate similar components in the differentembodiments. Some embodiments of the present invention relate to a leftatrial appendage implant that blocks and/or filters blood flow acrossthe ostium of the LAA. One such implantable device and system is knownto those of skill in the art as the PLAATO™ system from ev3 Inc.Additionally, some embodiments can include one or more featuresdescribed in connection with one or more of the embodiments describedherein.

Referring to FIG. 1, a schematic view of a patient's heart 10 in partialsection shows a transseptal sheath 12 having a distal end 14. The distalend 14 of the transseptal sheath 12 has breached the septum 18 of thepatient's heart 10 and is disposed within the left atrium 16 adjacentthe opening 20 of the patient's LAA 22. FIG. 2 illustrates a deploymentsystem 24, having an implant 26 and a delivery system 28. The implant 26may be designed to occlude or contain particles within the LAA 22 andprevent thrombus from forming in, and emboli from originating from, theLAA 22 in a patient with atrial fibrillation. The delivery system 28preferably is compatible for use with the transseptal sheath 12. Thedelivery system preferably comprises an axially movable core 30 and acontrol wire 32. The delivery system 28 and implant 26 preferably aredesigned to allow the implant 26 to be positioned, repositioned, andretrieved from the LAA 22 if necessary.

The implant 26 preferably comprises a frame 46 and a membrane (notshown). The implant 26 preferably extends from a proximal hub 50 at aproximal end 52 increasing in diameter to an apex or apex portion, thendecreasing to a distal hub 54 at a distal end 56. In some embodiments,the proximal hub 50 is coupled with a proximal crosspin 58. The distalhub 54 preferably is coupled with a plug or cap 60.

A plurality of supports 62 extend between a proximal hub 50 and a distalhub 54. In one embodiment, sixteen supports 62 are provided. However,the precise number of supports 62 can be modified, depending upon thedesired physical properties of the implant 26 as will be apparent tothose of skill in the art in view of the disclosure herein, withoutdeparting from the present invention.

Preferably, the supports 62 comprise a metal such as stainless steel,nitinol, Elgiloy, or others which can be determined through routineexperimentation by those of skill in the art. The frame 46 preferably isconstructed of self-expanding nitinol supports. Wires having a circularor rectangular cross-section may be utilized depending upon themanufacturing technique. In one embodiment, rectangular cross sectionsupports are cut such as by known laser cutting techniques from tubestock, a portion of which forms the hubs 50 and 54.

In the illustrated embodiment, the distal end 56 of the implant 26 isprovided with an implant plug or cap 60. In one embodiment, the implantplug 60 comprises an atraumatic tip, such that contact between theatraumatic tip and the inside surface of the LAA 22 does not causesignificant damage to the LAA 22.

Various distal end 56 constructions may be utilized, as will be apparentto those of skill in the art in view of the disclosure herein. In theembodiment illustrated in FIG. 2, the plug 60 may be attached to adistal end of a distal guide tube 66, described in greater detail below.The plug 60 may be secured to the guide tube 66 and implant 26 in any ofa variety of ways, depending upon the various construction materials.For example, any of a variety of metal bonding techniques such as awelding, brazing, interference fit such as threaded fit or snap fit, maybe utilized. Alternatively, any of a variety of bonding techniques fordissimilar materials may be utilized, such as adhesives, and variousmolding techniques. In one construction, the plug 60 is composed ofPEBAX.

The membrane (not shown) preferably is constructed of a fabric covering,such as one made of ePTFE, or an ePTFE/PE laminate. To attach themembrane to the frame 46, a PE mesh preferably is placed against thesupports 62, with one sheet of ePTFE preferably placed over the PE meshand another sheet of ePTFE preferably placed on an opposite side of thesupports 62. The membrane preferably is heated on both sides causing thePE to melt into both sheets of ePTFE, thereby surrounding a portion ofthe frame 46. The nitinol supports allow the implant 26 to self-expandin the appendage 22, covering the orifice with the laminated fabric. Theporous ePTFE/PE lamination facilitates rapid endothelialization andhealing. The membrane preferably covers at least a proximal face of thedevice.

The core 30 may comprise any of a variety of structures which hassufficient lateral flexibility to permit navigation of the vascularsystem, and sufficient axial column strength to enable reduction of theimplant 26 to its reduced crossing profile. Any of a variety ofstructures such as hypotube, solid core wire, “bottomed out” coil springstructures, or combinations thereof may be used, depending upon thedesired performance of the finished device. In one embodiment, the core30 comprises stainless steel tubing.

Referring to FIG. 2, the distal guide tube 66 extends proximally fromthe distal hub 54. The guide tube 66 receives the distal end of core 30within a recess or lumen defined by the guide tube 66. Followingpositioning at or about the desired deployment site, proximal retractionof the core 30 enables the implant 26 to radially enlarge under its ownbias to fit the surrounding tissue structure. The guide tube 66 may be asection of tubing such as metal hypotube, which is attached at thedistal end 56 of the implant and extends proximally within the implant26. The guide tube 66 preferably extends a sufficient distance in theproximal direction to inhibit buckling or prolapse of the core 30 whendistal pressure is applied to the core to reduce the profile of theimplant 26. However, the guide tube 66 should not extend proximally asufficient distance to interfere with the opening of the implant 26.

As will be appreciated by reference to FIG. 2, the guide tube 66 mayoperate as a limit on distal axial advancement of the proximal end 50 ofimplant 26. Thus, the guide tube 66 preferably does not extendsufficiently far proximally from the distal end 56 to interfere withoptimal opening of the implant 26. The specific dimensions are thereforerelative, and will be optimized to suit a particular intendedapplication. In one embodiment, the implant 26 has an implanted outsidediameter within the range of from about 5 mm to about 45 mm, and anaxial implanted length within the range of from about 5 mm to about 45mm. The guide tube 66 may have an overall length of about 3 mm to about35 mm, and an outside diameter of about 0.095 inches.

Further details regarding methods and apparatuses for accessing the LAAand LAA devices and related methods are disclosed in U.S. Pat. No.7,056,294, filed Mar. 15, 2002; and U.S. patent application Ser. No.10/642,384, filed Aug. 15, 2003 and published as U.S. Pat. Pub. No.2005/0038470. The entirety of each of these is hereby incorporated byreference.

A transseptal sheath 12 is illustrated in FIG. 3. The transseptal sheath12 may comprise an elongate, flexible tubular body 64, a control handle66, and a balloon tip 68. In one embodiment, a tubular body 64preferably is steerable using the handle 66 to facilitate access to theleft atrium. The handle 66 may be coupled to a proximal end 80 of thesheath 12 to steer the distal end 14 of the transseptal sheath 12 and tocontrol deployment and recapture of the implantable device. The handle66 may be used to adjust the angulation, orientation, position, and/orpitch of the transseptal sheath 12. In some embodiments, the transseptalsheath may be designed to facilitate access to physiological structures,such as the LAA, the orifice of the LAA, the distal aspect of the LAA,or pulmonary vein such as the left superior pulmonary vein. One ofordinary skill in the art can determine the geometric orientation of thesheath that is suitable for any particular application based on thedesired region of access and the particular patient's physiology throughroutine experimentation in view of the disclosure herein. In oneembodiment that is useful for accessing regions of the LAA, a tubularbody 64 may be steered such that the transseptal sheath 12 comprises afirst curved section 70 to facilitate location of the fossa ovalis onthe intraatrial septum and a second curved section 72 to facilitatelocation and access of the desired region of the LAA after penetrationof the fossa ovalis. This may be accomplished by providing the sheath 12with any of a variety of steering mechanisms, which allow a distalportion of the sheath to be inclined away from the axis of the normalbias of the catheter. For example, one or more axially moveable pullwires may extend through the length of the sheath. Proximal traction ona pull wire that is secured at a distal location of the catheter willcause a lateral deflection of the catheter. Other techniques will beknown to those of skill in the art. Further details regarding steerablesheaths are disclosed in U.S. Pat. No. 7,056,294, filed Mar. 15, 2002,the entirety of which has been incorporated by reference.

One of ordinary skill in the art will recognize that the precise shapeof these curves will depend on the patient's physiology and can bedetermined through routine experimentation. Accordingly, the firstcurved section 70 and the second curved section 72 may be steeredthrough a range of angulations. For example, second curved section 72may be steered through a range of angulations from about 0 .degree. toabout 180 .degree., as shown in FIG. 4.

Typically, the location of a non-steerable transseptal sheath ismaintained using a super stiff J tip wire. Use of a steerable sheathpermits use of a lighter, less traumatic wire, or even delivery andpositioning of the transseptal sheath without any guidewire, saving timeand effort. It also helps reduce the possibility of sheath contentembolization during multiple swapping of internal catheters prior toimplant system introduction. A steerable transseptal sheath may have athicker sheath wall than a non-steerable sheath to accommodate asteering wire and a balloon inflation lumen, and this thicker sheathwall is more robust and resilient. This is helpful for maintainingspatial orientation during left atrial appendage implant introductionand manipulation. It also increases column strength of the sheath duringhigh loading conditions, such as recapture. In one embodiment, the wallof the transseptal sheath may be about 3 mm thick.

The balloon tip 68 may provide an atraumatic end 100 to sheath 12 toavoid damage to the anatomy when they contact each other. Referring toFIG. 4, the balloon tip 68 preferably is located at a distal end 14 ofthe transseptal sheath 12. In a deflated state the balloon tip 68 mayhave an inner diameter and an outer diameter generally equal to those ofthe tubular body 64, as shown in FIG. 5. When inflated, the balloon tip68 may have a maximum outer diameter larger than the outer diameter ofthe tubular body 64, a minimum inner diameter smaller than the innerdiameter of the tubular body 64, or both, as illustrated in FIG. 6. Theballoon tip 68 may inflate to an outer diameter of about 4 mm or less toabout 30 mm or more. In one embodiment, the balloon may inflate to anouter diameter of about 6 mm. The balloon tip 68 when inflated may havea larger diameter near a distal end 76 than near a proximal end 74. Inanother embodiment, the balloon tip may inflate to a diameter as largeas or slightly larger than that of the left atrium.

The balloon tip 68 may be about 3 mm or less to about 12 mm or morelong. In one embodiment the balloon tip 68 may be about 10 mm long. Theinterior length and the exterior length may be different. In oneembodiment, the interior length is about 10 mm while the exterior lengthis about 5 mm. Alternatively, the exterior length may be greater thanthe interior length. The balloon tip 68 may also increase in length whenit is inflated. The length may increase by about 1 mm or less to about 3mm or more. In one embodiment, the balloon tip 68 may increase in lengthby about 1.5 mm when inflated. The inflated balloon tip 68 may extenddistally from the tubular body 64 to soften the distal end 14 of thesheath 12, as shown in FIG. 6. The distal extension of the balloon tip68 from the tubular body 64 may correspond to the increase of theballoon's length when it is inflated. It should also be appreciated thatthe balloon tip 68 may be inflated to a size smaller than its maximumsize.

The sheath may comprise a channel or lumen 78 for inflating the balloontip 68, as shown schematically in FIG. 7. In one embodiment, the balloontip 68 may be inflated with saline. In another embodiment, the balloontip 68 may be inflated with fluid comprised of radiopaque fluid such ascontrast media. The balloon may be made from any of a variety ofmaterials well known to those of skill in the art, including latex,polyurethane, polymers, rubber, PEBAX, or any other known elasticmaterial. In one embodiment, the balloon is made from silicone rubber.

The deployment system 24, shown schematically in FIG. 7, may comprise atransseptal sheath 12, a balloon tip 68, a delivery catheter 82, anaxially movable core 30, a control wire 32, and an implant 26 (shownschematically). Details of the deployment system and implant aredescribed in U.S. patent application Ser. No. 10/642,384, filed Aug. 15,2003 and published as U.S. Pat. Pub. No. 2005/0038470, the entirety ofwhich has been incorporated by reference. The balloon tip 68 may beconnected to a distal end 14 of the sheath 12. The delivery catheter 82may be disposed within the sheath 12. The axially movable core 30 andthe control wire 32 may extend through the delivery catheter 82 andconnect to the implantable device 26. The deployment system 24 may beused to deploy the implant 26 within a LAA.

To deliver the system, a preferred access point is along the rightfemoral vein, although access from the left femoral vein is alsopossible. Access may also be achieved through a puncture in any of avariety of other veins of suitable internal diameter and the presentinvention is not limited in this regard.

A conventional spring tipped guidewire is thereafter advanced throughthe needle into the vein and the needle is subsequently removed. Adilator preferably is positioned within a transseptal or outer sheath ofthe type described herein, or other well-known sheaths, such as a 14French introducer sheath. Subsequently, the transseptal sheath anddilator, in combination with the guidewire, are advanced through thefemoral vein to the right atrium.

Referring to FIG. 8, there is illustrated a schematic cross-section of aportion of the heart 10. The right atrium 86 is in communication withthe inferior vena cava 88 and the superior vena cava 90. The rightatrium 86 is separated from the left atrium 16 by the intraatrial septum18. The fossa ovalis 92 is located on the intraatrial septum 18. As seenin FIG. 8, the transseptal sheath 12 may have the dilator 84 and aguidewire 94 therein, may be positioned within the right atrium 86. Inone embodiment, the transseptal sheath has an inside diameter of about12 Fr and an outside diameter of about 15 Fr. The transseptal sheathwall thickness is about 1 mm. In other embodiments, the transseptalsheath wall thickness is about 0.5 mm, about 1.5 mm, or about 2 mm. Insome embodiments the transseptal sheath wall thickness is not more thanabout 2.5 mm.

The guidewire 94 is thereafter distally advanced to access the superiorvena cava 90. See FIG. 9. The dilator 84 and sheath 12 are thereafteradvanced into the superior vena cava as illustrated schematically inFIG. 10. The guidewire 94 may be proximally retracted. An advantage ofembodiments of the present invention is that the transseptal sheath maybe steered to a desired location independent of other components ordevices. In addition, the sheath may be steered either with or withoutthe implantable device being located therein.

When the sheath 12 and the dilator 84 are in the superior vena cava 90and the guidewire 94 has been removed if one has been employed, atransseptal needle 96 may be advanced through the dilator 84 and sheath12. The transseptal needle 96 is advanced (possibly with a stylet inplace) to a point that the stylet tip is just inside the distal tip ofthe sheath 12 and dilator 84, a position previously noted by theoperator, and the stylet is withdrawn from the transseptal needle.

The remaining combination of the sheath 12 with the dilator 84 havingthe transseptal needle 96 therein, is then drawn proximally from thesuperior vena cava while the first curved section 70 of the sheath,alone or in combination with a preset curve at the distal region ofdilator 84, causes the tip of the sheath-dilator-transseptal needlecombination to “drag” along the wall of the right atrium 86 and theseptum 18, as illustrated in FIGS. 10 and 11.

The tip of the dilator 84 is then positioned against the septum 18 bydistal advancement through the sheath 12. The tip is then dragged alongthe septum by proximal traction on the dilator 84 until the tip popsonto the fossa ovalis 92, as shown in FIG. 11.

The physician is normally assisted during placement, as in the entireprocedure, by fluoroscopy or other visualization techniques. To assistin such visualization, the distal tip of sheath 12 and the distal tip ofdilator 84 may be provided with a radiopaque marker. In addition, somephysicians find it desirable to infuse a radiopaque dye through thetransseptal needle 96 at various stages of the procedure to assist invisualization, particularly following the transseptal puncture.

After the tip of the sheath-dilator-transseptal needle combination hasbeen placed in the desired location against the fossa ovalis 92, thetransseptal needle 96 is abruptly advanced to accomplish a quickpuncture (see FIG. 12). In one embodiment the needle is advanced byapplying a force to the proximal end of the needle. In this embodimentthe needle often comprises a stiff proximal section and a flexibledistal section. The distal section preferably comprises ribbon coil.

Immediately after the puncture, one medical technique is to confirm thepresence of the tip 98 of the transseptal needle 96 within the leftatrium 16. Confirmation of such location of the tip 98 of thetransseptal needle 96 may be accomplished by monitoring the pressuresensed through the transseptal needle lumen to ensure that the measuredpressure is within the expected range and has a waveform configurationtypical of left atrial pressure. Alternatively, proper position withinthe left atrium 16 may be confirmed by analysis of oxygen saturationlevel of the blood drawn through the transseptal needle 96; i.e.,aspirating fully oxygenated blood. Finally, visualization throughfluoroscopy alone, or in combination with the use of dye, may also serveto confirm the presence of the tip 98 of the transseptal needle 96 inthe left atrium 16.

After placing the transseptal needle tip 98 within the left atrium 16,the tip of the dilator 84 is advanced through the septum 18 and into theleft atrium 16, as shown in FIG. 13. Typically, care is taken to ensurethat, at the same time of advancing the dilator and sheath tip into theleft atrium, the tip of the transseptal needle is not advanced asufficient distance that the needle 96 can damage the opposing wall ofthe left atrium 16. When the tapered tip of dilator 84 appears to haveentered the left atrium 16, the transseptal needle 96 is withdrawn. Thesheath 12 is then advanced into the left atrium 16, either by advancingthe sheath 12 alone over the dilator 84 or by advancing the sheath 12and dilator 84 in combination (see FIG. 14). The dilator 84 is thenwithdrawn from sheath 12 when the latter has been advanced into the leftatrium, thus leaving the main lumen of sheath 12 as a clear pathway toadvancing further diagnostic or therapeutic instruments into the leftatrium, as shown in FIG. 15.

It will be appreciated that other techniques may be used to deliver atransseptal sheath to the left atrium or to other locations in the body.For example, the sheath need not pass through the fossa ovalis, but maybe delivered through another portion of the septum.

In one embodiment, illustrated in FIGS. 8-16, the sheath 12 comprises aninflatable balloon 68 at the distal end 14 and means for inflating theballoon 78 (see FIG. 7), such as an inflation lumen. The balloon 68preferably is in a deflated position as the sheath 12 crosses the fossaovalis 92 to access the left atrium. The balloon tip 68 may be inflatedafter it crosses the fossa ovalis 92, as shown in FIG. 16. In thoseembodiments where the balloon 68 is inflated to a diameter greater thanthe diameter of the sheath 12, the balloon 68 prevents the sheath fromunintentionally passing back through the fossa ovalis during subsequentprocedures. The inflated balloon 68 creates an atraumatic distal tipthat can be navigated to access a location of interest, such as the LAA,without use of any additional device or catheters to blunt the edge ofthe transseptal sheath 12. The balloon tip 68 may be inflated to adiameter of about 4 mm or less to about 12 mm or more. In oneembodiment, the balloon tip 68 is inflated to a diameter of about 6 mmto prevent the sheath from passing back through the septum and toprovide an atraumatic tip for probing the LAA.

Referring to FIG. 17, the transseptal sheath 12, with the balloon 68inflated, may be advanced to the LAA 22. In one embodiment, a steerabletransseptal sheath 12 may be advanced into the LAA without use of aguidewire. In another embodiment, the transseptal sheath 12 may beadvanced into the LAA by guiding it over a guidewire. The balloon tip 68allows the transseptal sheath 12 to be used for LAA access,visualization and probing, including mechanical probing or “feeling out”the inside wall of the heart, as illustrated in FIG. 18, without causingtrauma. When steerable transseptal sheath 12 and a balloon tip 68 areused careful probing over a guidewire, a pigtail catheter and transitioncatheter are unnecessary. This is an advantage as it is known, whenusing guidewires, to puncture the LAA membrane with sequelae such ascardiac tamponade, epicardial perfusion, or other adverse events.

The balloon tip 68 may generally comprise an atraumatic end 100 toprevent trauma to the inside wall of the LAA 22 during deployment,anchoring, and advancement of the implantable device 26. The atraumaticend 100 can be the distal surface 102 of the balloon tip 68, or it canbe an atraumatic surface attached to the distal surface 102 of theballoon tip 68. The atraumatic end 100 can be made from any of a varietyof materials well known to those of skill in the art, including latex,polyurethane, polymers, rubber, plastic, PEBAX, or any other knownatraumatic material. In one embodiment the atraumatic end is made fromsilicone.

Once the distal end of the transseptal sheath is in the LAA, the LAA'smorphology is assessed. For example, the morphology can be assessed byinjecting contrast into the left atrial appendage and viewing the heartunder fluoroscopy. More than one lobe is present in the LAA more than60% of the time. In one embodiment, a steerable transseptal sheath 12may be used to explore multiple locations within the LAA to ascertainthe morphology of the LAA and determine the optimal and/or desiredimplant location.

The transseptal sheath 12 may be secured in place by pressing or wedgingthe inflated balloon tip 68 of the transseptal sheath 12 into the narrowwall of the left atrial appendage, as shown in FIG. 19. The balloon tip68 may be further inflated to maintain the transseptal sheath 12 in theLAA 22 during equipment exchange through sheath lumen. This avoids thepossibility of the transseptal sheath 12 accidentally exiting the LAA 22or the left atrium during implantable device delivery. In this manner,the outer sheath can be anchored in place without piercing or otherwisecutting, poking, or pinching the inside wall of the heart, including theinside wall of the atria, ventricles, or atrial appendages. Anchoringthe outer sheath in place facilitates imaging of the appendage by way ofinjection of radiopaque materials followed by techniques such asfluoroscopy.

Once the desired location for implant delivery has been identified andthe distal end 14 of the transseptal sheath 12 has been secured inplace, the implantable device may be introduced into the transseptalsheath 12. Alternatively, the implantable device may have been preloadedinto the transseptal sheath. The position of the transseptal sheath 12preferably is maintained while advancing the implantable device throughthe transseptal sheath 12 to the LAA 22. If the distal end 14 of thetransseptal sheath 12 shifts or is otherwise moved out of the desiredlocation it may be steered back to the proper position.

Referring to FIG. 20, the implantable device 26 may be advanced untilits distal end 56 is within about 2 mm or less to about 10 mm or morefrom the distal end 14 of the sheath 12. In one embodiment theimplantable device 26 is advanced within about 5 mm of the distal end 14of the sheath 12. When in position, the balloon tip 68 may bedeactivated so it no longer locks the distal end 14 of the sheath 12within the LAA 22. Alternatively, the balloon tip 68 may remaininflated. The sheath 12 may then be retracted proximally to expose theimplantable device 26, as illustrated in FIG. 21.

The implantable device 26 may then be deployed, as shown in FIG. 22,using any of a variety of mechanisms known to those of skill in the art.In some embodiments, the implantable device 26 is self-expanding, andexpands upon retraction of the sheath 12. If a self-expandingimplantable device is used, the implantable device 26 preferably ispositioned in the desired location before refraction of the sheath 12.

If it is desired to recapture, replace, and/or retrieve the implantabledevice 26 once deployed, the distal end 14 of transseptal sheath 12 maybe maintained in the left atrium by inflating the balloon tip 68 (seeFIG. 23). The inflated balloon tip 68 may thereby provide an atraumaticstop that does not pass proximally septum 18 into the right atrium 86(see FIG. 16).

When the implantable device appears to have been successfully positionedat the desired location, final contrast injections may be providedthrough the transseptal sheath to assess the implant's condition. Thetransseptal sheath may be steered to various locations within the heartto allow for complete fluoroscopic assessment. The balloon tip maybeinflated at this time to provide an atraumatic interface between thetransseptal sheath's distal end and the inner wall of the heart. Whenassessment is completed the balloon tip 68 is returned to itsreduced-diameter configuration, and the transseptal sheath is withdrawnfrom the patient's body. If necessary, access to the LAA can bere-established according to the method described above.

In another embodiment, the transseptal sheath 12 may be inserted intothe LAA 22 with the balloon tip 68 deflated, as illustrated in FIG. 24.Once at the deployment site, the balloon tip 68 is inflated to securethe distal end 14 of the sheath 12 in place during advancement of theimplantable device 26 through the outer sheath, as shown in FIG. 25. Inone embodiment, the balloon tip 68 is inflated to a diameter of about 24mm to secure the distal end 14 of the sheath 12 in LAA 22. In someembodiments, the balloon tip 68 may comprise ribs, hooks, barbs,anchors, bands, rings, or other friction devices to secure the distalend of the outer sheath in place when activated.

Once the sheath 12 has been anchored in place with the balloon tip 68,the delivery catheter 82 advances the implantable device 26 through thesheath 12, as shown in FIG. 26A. The implantable device 26 may beadvanced until its distal end 56 is within about 2 mm or less to about30 mm or more beyond distal end 14 of the sheath 12, as illustrated inFIGS. 26A and 26B. In one embodiment the implantable device 26preferably is advanced within about 10 mm or more from the distal end 14of the sheath 12, and more preferably within about 8 mm of the distalend 14 of the sheath 12. Positioning of the implantable device 26 withinthe sheath 12 and within the heart may be confirmed by any visualizationtechnique known to those of skill in the art. For example, in oneembodiment, the position of the implant 26 is determined by fluoroscopyor another imaging technique.

In one embodiment, the balloon tip 68 may be deflated, so it no longersecures the distal end 14 of the sheath 12, when the implantable device26 is near the distal end 14 of the sheath 12, but still within thesheath 12, as shown in FIG. 27. The sheath 12 may then be retractedproximally, and/or the implantable device 26 may be distally extended,to expose the implantable device 26, as illustrated in FIG. 28B. Inanother embodiment, the implantable device 26 may be advanced until itis completely or partially protruding from the sheath 12, as shown inFIG. 26B, then the balloon tip 68 may be deflated, as shown in FIG. 28A.The sheath may then be proximally retracted, as illustrated in FIG. 28B.The implantable device 26 may then be expanded using any of a variety ofmechanism well known to those of skill in the art. In some embodiments,the implantable device 26 is self-expanding, and expands upon refractionof the sheath 12. FIG. 29 shows the implantable device 26 expandedwithin the LAA 22. Further steps may be employed for recapture andrepositioning of the device by reinflation of the balloon 68 andrepositioning of the transseptal sheath.

In some embodiments, the distal end of the transseptal sheath may besecured in place without using a balloon tip. For example, the distalend of the sheath may comprise ribs, hooks, barbs, anchors, bands,rings, or other friction devices to secure the distal end of the sheathin place.

Embodiments of the invention are used to treat other bodily openings,lumen and cavities, besides the left atrial appendage. For example, insome embodiments, the methods, devices and systems described herein areused to treat any heart opening or defect, such as a patent foramenovale (PFO), an atrial septal defect (ASD), a ventricular septal defect(VSD), a patent ductus arteriosus (PDA), an aneurysm and/or anaortico-pulmonary window. Embodiments of the invention are also usedduring treatment of other conditions requiring the use of mitral valveleaflet clips, percutaneously implanted valves such as mitral or aorticvalves, or during treatment of chordae tendonae for alteration of mitralvalve prolapse.

In addition, while particular forms of the invention have beendescribed, it will be apparent that various modifications can be madewithout departing from the spirit and scope of the invention.Accordingly it is not intended that the invention be limited to theparticular embodiments described herein.

1. (canceled)
 2. A method of delivering an implantable device to a leftatrial appendage, comprising: delivering a first sheath comprising anelongate body having a central lumen sized and adapted to deliver animplantable device therethrough, a distal balloon located at a distalend thereof, and an inflation lumen operably connected to the distalballoon to a right atrium; advancing the first sheath distal end throughan intraatrial septum and into a left atrium; inflating the distalballoon of the first sheath, thereby providing the first sheath with anatraumatic tip which extends distally beyond the distal end of the firstsheath and radially therefrom; positioning a distal end of the distalballoon adjacent a left atrial appendage; delivering an implantabledevice through the first sheath to the left atrial appendage; deflatingsaid distal balloon; and removing said first sheath.
 3. The method ofclaim 2, wherein the first sheath includes a distal end steerable from aproximal end of the first sheath without moving the proximal end of thefirst sheath.
 4. The method of claim 3, wherein positioning includessteering the distal end of the first sheath from the proximal end of thefirst sheath.
 5. The method of claim 2, wherein the distal balloon has adeflated configuration in which an inner diameter and an outer diameterof the distal balloon are generally equal to the corresponding diametersof the adjacent portion of the first sheath.
 6. The method of claim 2,wherein inflating includes introducing saline into the distal balloonthrough the inflation lumen of the first sheath.
 7. The method of claim2, wherein inflating includes introducing a radiopaque fluid into thedistal balloon through the inflation lumen of the first sheath.
 8. Themethod of claim 2, wherein positioning includes positioning the distalballoon within the left atrial appendage and further inflating thedistal balloon.